The investigation of multi-touch surfaces on smartphones is a relevant topic in the field of human-computer interaction. The main focus is to analyze and to understand touch input in detail, as well as delivering comprehensible insights for user interface designers and developers.

The main part of this work is an empiric study with 22 participants and its analysis. In three conditions the participants had the task to tap on randomly appearing squares. Each participant had to accomplish 3420 trials in general. The taps were analysed and also visualized in terms of performance, error rates and touch-offsets. The results show that the highest performance of a tap is in a easy reachable region and that it is the most accurate to tap targets with the index finger of your dominant hand, while holding the smartphone with your non dominant hand. Within a follow-up project the existing data of the main study was used to implement and analyse an algorithm which reduced the failrate of the taps. For the future, we plan to utilize gamification to conduct a large scale public study for further investigation on multi-touch surfaces.